GCr15表面TiC/Fe复合层的制备及其与基体结合性能分析

研究以GCr15和TC4为原料，采用热压扩散原位反应在GCr15表面制备TiC/Fe复合层. 利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、自动划痕仪和显微硬度仪测试表征复合层的物相组成、显微组织、复合层的界面结合性能和显微硬度的变化. 结果表明，在1000 ℃和40 MPa条件下保温2 h，4 h和6 h后，TiC/Fe复合层厚度分别为5 μm，7 μm和10 μm，复合层厚度均匀，与基体界面平整，其表面物相组成仅为TiC和α-Fe相，复合层的显微硬度最高达到2453.7 HV0.05，约为轴承钢基体的5倍. 显微划痕与拉伸试验可知1000 ℃和40 MPa条件下保温4 h所得复合层与基体界面结合的临界载荷为58.5 N，界面结合强度大于221 MPa，表明热压扩散原位制备GCr15表面TiC/Fe复合层与基体之间具有优异的结合性能，对基体保护作用良好.

Preparation of TiC/Fe composite layer on the surface of GCr15 and its binding performance with matrix

In this study, A TiC/Fe composite layer was prepared on the surface of GCr15 using hot pressure diffusion in situ reaction. X-ray diffractometer (XRD), scanning electron microscopy (SEM), automatic scratching instrument and microhardness apparatus were used to characterize the phase composition, microstructure, interface binding properties of the composite layer and changes in microhardness. The results show that the thickness of the TiC/Fe composite layer after insulation for 2 h, 4 h and 6 h at 1 000 ℃, 40 MPa is 5 μm, 7 μm and 10 μm, respectively, the thickness of the composite layer is uniform, the interface with the matrix is flat. The surface phase composition is only TiC and α-Fe phase, and the microhardness of the composite layer is up to 2 453.7 HV0.05, which is about 5 times that of the bearing steel matrix. Micro scratching and tensile tests show that the critical load of the composite layer bonding to the matrix interface at 1 000 ℃, 40 MPa for 4 h is 58.5 N, and the interfacial bonding strength is greater than 221 MPa. The results show that the TiC/Fe composite layer on the surface of GCr15 prepared by hot compression diffusion in situ has excellent binding properties and good matrix protection effect.